The present invention relates to a design evaluating method for assisting a circuit-board-assembly, evaluating assemblability of a circuit board on which electronic components are mounted, a computer-readable recording medium having recorded thereon computer-executable evaluation-assisting programs for executing the design evaluating method for assisting the circuit-board-assembly, and a design evaluating apparatus for assisting the circuit-board-assembly for executing the design evaluating method for assisting the circuit-board-assembly.
It is noted that a term xe2x80x9cdesign and assembly operation,xe2x80x9d herein refers to processes ranging from an operation of circuit design and electronic components selection to a completion of engineering-trial manufacture of a component-mounted-circuit board, which is a printed circuit board (which hereinafter may be referred to also as xe2x80x9cPCBxe2x80x9d) that has electronic components mounted thereon and that fulfills desired functions, on the ground that assembly easiness of electronic components onto the circuit board depends not only on an assembly operation but also, actually, on a process of the circuit design. Therefore, the design evaluation in turn means determining the degree of how design techniques and assembly techniques included in the respective processes ranging from the circuit design to the engineering-trial manufacture of the component-mounted-circuit board as described above are satisfying preset targets of the design techniques and the assembly techniques.
In designing a circuit board that is used in some articles, for example, electronic equipment such as televisions and video cassette recorders and that fulfills desired functions, it has been conventional practice to take such steps as shown in FIG. 86. That is, after system design for the whole electronic equipment as shown in Step (denoted by xe2x80x9cSxe2x80x9d in the figure) 1, the design of circuits capable of executing functions of the system as well as the selection of electronic components to be provided in the circuits are performed based on a system design corpus at Step 2. Based on circuit diagrams and component lists relating to these circuit design and selected components, circuit board and pattern design is performed at Step 3. Based on the resulting board design drawings and pattern design drawings, at step 4, a prototype of a component-mounted-circuit board in which electronic components are mounted on the circuit board is manufactured. At Step 5, performance evaluation is performed on the prototype component-mounted-circuit board, where if specified performances are satisfied, then the component-mounted-circuit board is trial manufactured. Then, with regard to the prototype, a quality evaluation is performed at Step 7, a manufacturing cost evaluation is performed at Step 8, and a production evaluation is performed at Step 9 as to whether or not the protoptype is producible without trouble by a production line, one after,the other based on experiences and the like. If the evaluations of Steps 7 to 9 are all satisfied, then a regular production of the component-mounted-circuit board is started. In addition, if the specified performances are not satisfied in the evaluations of Step 5 and Steps 7 to 9, then the process flow is fed back to any one of the Steps 12, 13 and 14, where the processing steps are executed again starting with the operation of circuit-board redesign and electronic-component reselection, or the redesigning for circuit board and pattern design, or redoing of trial manufacture of the component-mounted-circuit board. In this case, which step among Steps 12, 13 and 14 the process flow is fed back to is decided based on the results of the performance evaluations.
Like this, in the conventional art, as shown by Step 5, the assemblability evaluation would not be enabled until the completion of circuit board design and pattern design and the manufacture of the prototype of the component-mounted-circuit board, and as to failures found by the evaluation, the circuit design and the electronic components selection and the like would be redone and a prototype of the component-mounted-circuit board would be manufactured once again.
As shown above, in the conventional art, since the circuit board with electronic components mounted thereon could not be evaluated for its design and manufacture until the circuit board is once completed, there have been problems such as a prolonged design-and-development lead time, a low level of design completeness, and a low productivity and flexibility for variations.
Also, in each of the steps from the operation of circuit design and electronic components selection to the manufacture of the prototype of the component-mounted-circuit board, it has conventionally been practiced that design and manufacture are performed based on personal knowledge and judgment of the design operators or manufacture operators. Thus, in the conventional art, there is no evaluation means for objectively and impartially judging whether or not techniques adopted for the respective steps by the design operator or manufacture operator are the best ones for circuit boards of the system. Neither is there evaluation means which allows a technique that the design operator or manufacture operator is planning to adopt for any one of the steps, to be objectively and impartially evaluated at a planning stage for the adoption of the technique.
In addition, a publication of unexamined Japanese Patent application 4-359497 has disclosed a circuit-board productivity design automatic evaluation system in which it is automatically quantitatively evaluated, prior to the making of a prototype of the component-mounted-circuit board, whether or not the structure of a designed circuit board is easy to produce, and in particular, easy to assemble. However, the invention disclosed in the publication is designed to enable quantitative evaluation of assembly easiness of the circuit board in the stage where the designed circuit board has been forwarded to a manufacturing process. That is, in the invention of the publication, for the evaluation of the assembly easiness without requiring any abundance of experiences, assembling operations in the process of assembling the components onto the circuit board are previously classified into basic factors and correction factors, and then the assembling operations with the circuit board to be evaluated or components are represented by combinations of the basic factors and the correction factors, in which arrangement of the assembly easiness of the circuit board is quantitatively evaluated based on the combinations.
Like this, the invention of the above publication indeed enables the design evaluation prior to the trial manufacture, but is so constituted as to enable the evaluation of the assembly easiness, i.e. productivity design, of the circuit board based on factors relating to the assembling operations, i.e., factors relating to manufacture.
Accordingly, in not only the invention of the above publication but in the conventional art, there exists no one that quantitatively evaluates the assemblability of circuit boards comprehensively by taking into consideration factors other than factors relating to the manufacture, that is, factors relating to the design of the circuit board, factors relating to production technology including manufacturing know-how, and factors relating to manufacture with a manufacturing equipment taken into account, in other words, that quantitatively evaluates the assemblability of circuit boards comprehensively on a scale common to the three divisions of design, production technology and manufacturing.
Further, in the invention of the aforementioned publication, whereas it is considered that the classification into the basic factors and the correction factors is performed based on the experiences of those skilled in the art, whether or not the classification is objectively correct is not determinate, so that the evaluation of the assembly easiness lacks objectivity. Therefore, the invention of the publication is not one that enables objective and impartial evaluation.
Furthermore, in the invention of the publication, the assembly easiness of the circuit board is evaluated with the aim of improving the production efficiency of the circuit board. Accordingly, there has conventionally been provided no one that executes the assemblability evaluation for enabling the realization of high-quality assembly simply without involving considerations for improvement in the production efficiency, even with the invention of the above publication taken into account.
The present invention has been accomplished to solve these and other problems. An object of the present invention is therefore to provide a design evaluating method for assisting circuit-board-assembly, a computer-readable recording medium having recorded thereon computer-executable evaluation-aid programs for executing the design evaluating method, and a design evaluating apparatus for assisting the circuit-board-assembly, executing the design evaluating method, each of which enables high-quality assembly to be realized by taking into consideration factors relating to a design of the circuit board, factors relating to production technology including know-how in manufacture, and factors relating to manufacture with manufacturing equipment, and by objectively and impartially evaluating the assemblability of circuit boards comprehensively on a scale common to these factors.
In a first aspect of the present invention, there is provided a design evaluating method for assisting circuit-board-assembly regarding design and assembly operation which includes designing a circuit that fulfills desired function, designing a pattern on a circuit board to form the circuit, and then performing engineering-trial manufacture of a component-mounted-circuit board mounting components on the circuit board, the method comprising:
at a stage prior to the engineering-trial manufacture of the component-mounted-circuit board, performing a first design evaluation or a second design evaluation with considerations given to both sides of design and assembly processes, the design process side where the circuit design and the pattern design are involved and the assembly process side where electronic components are mounted onto the circuit board,
wherein the first design evaluation is design evaluation for, with respect to the circuit design and electronic components selection, evaluating differences between an actually performed circuit design and a target circuit design, and between components selection and target components selection, the target circuit design and the target components selection being targeted for quality improvement in an assembly operation, in the assembly process, of mounting the electronic components onto the circuit board, and the second design evaluation is design evaluation for, with respect to design of the circuit board and the pattern design of the circuit board, evaluating differences between an actually performed circuit board design and a target board design, and between a pattern design and a target pattern design, the target board design and the target pattern design being targeted.
In a second aspect of the present invention, there is provided a design evaluating method for assisting circuit-board-assembly regarding design and assembly operation which includes designing a circuit that fulfills desired function, designing a pattern on a circuit board to form the circuit, and then performing engineering-trial manufacture of a component-mounted-circuit board mounting components on the circuit board, the method comprising:
at a stage prior to the engineering-trial manufacture of the component-mounted-circuit board, performing a first design evaluation and a second design evaluation with considerations given to both sides of design and assembly processes, the design process side where the circuit design and the pattern design are involved and the assembly process side where electronic components are mounted onto the circuit board, wherein the first design evaluation is design evaluation for, with respect to the circuit design and electronic components selection, evaluating differences between an actually performed circuit design and a target circuit design, and between components selection and target components selection, the target circuit design and the target. components selection being targeted for quality improvement in an assembly operation, in the assembly process, of mounting the electronic components onto the circuit board, and the second design evaluation is design evaluation for, with respect to design of the circuit board and the pattern design of the circuit board, evaluating differences between an actually performed circuit board design and a target board design, and between a pattern design and a target pattern design, the target board design and the target pattern design being targeted.
In the design evaluating method for assisting circuit-board-assembly of the first or second aspect, the first design evaluation may comprise at least calculating assembly cost for the assembly operation and, with respect to evaluation of the circuit design and the electronic components selection as well as evaluation of the circuit design and the electronic components selection as viewed from the assembly process side where the electronic components are mounted onto the circuit board, evaluating any difference between the target circuit design and the actually performed circuit design as well as any difference between the target components selection and the actually performed components selection.
Also, the evaluation of the circuit design and the electronic components selection may comprise an evaluation as to whether or not the circuit design and electronic components selection of a circuit to be designed has progressed with respect to a comparison target.
Also, the evaluation of the circuit design and the electronic components selection further may comprise at least an evaluation of compliance with design criteria for quality improvement with respect to the circuit design and electronic components selection, and an evaluation of compliance with know-how items in the assembly process for the quality improvement with respect to the circuit design and electronic components selection.
In a third aspect of the present invention, there is provided a computer-readable recording medium having recorded thereon programs for making the computer execute design evaluating processing for assisting circuit-board-assembly regarding design and assembly operation which processing includes designing a circuit that fulfills desired function, designing a pattern on a circuit board to form the circuit, and then performing engineering-trial manufacture of a component-mounted-circuit board mounting components on the circuit board,
at a stage prior to the engineering-trial manufacture of the component-mounted-circuit board, recording design evaluation processing programs for assisting circuit-board-assembly, the programs including instructions for making the computer execute a first design evaluation process or a second design evaluation process with considerations given to both sides of design and assembly, the design side where the circuit design and the pattern design are involved and the assembly side where electronic components are mounted onto the circuit board,
where the first design evaluation process is design evaluation process for, with respect to the circuit design and electronic components selection, evaluating differences between an actually performed circuit design and a target circuit design, and between components selection and target components selection, the target circuit design and the target components selection being targeted for quality improvement in an assembly operation, in the assembly process, of mounting the electronic components onto the circuit board, and the second design evaluation process is design evaluation for, with respect to design of the circuit board and a pattern design of the circuit board, evaluating differences between an actually performed circuit board design and a target board design, and between a pattern design and a target pattern design.
In a fourth aspect of the present invention, there is provided a design evaluating apparatus for assisting circuit-board-assembly, the apparatus for executing design evaluation for assisting circuit-board-assembly regarding design and assembly operation which includes designing a circuit that fulfills desired function, designing a pattern on a circuit board to form the circuit, and then performing engineering-trial manufacture of a component-mounted-circuit board mounting components on the circuit board, the apparatus comprising:
a reading unit for reading a program recorded on the recording medium as defined in the thied aspect of the present invention; and
an evaluation executing unit for executing a first design evaluation or a second design evaluation with considerations given to both sides of design and assembly processes, the design process side where the circuit design and the pattern design are involved and the assembly process side where electronic components are mounted onto the circuit board, based on the read program at a stage prior to the engineering-trial manufacture of the component-mounted-circuit board.
In a fifth aspect of the present invention, there is provided a design evaluating apparatus for assisting circuit-board-assembly, the apparatus executing design evaluation for assisting circuit-board-assembly regarding design and assembly operation which includes designing a circuit that fulfills desired function, designing a pattern on a circuit board to form the circuit, and then performing engineering-trial manufacture of a component-mounted-circuit board mounting components on the circuit board, the apparatus comprising:
an evaluation executing unit for executing a first design evaluation and a second design evaluation with considerations given to both sides of design and assembly processes, the design process side where the circuit design and the pattern design are involved and the assembly process side where electronic components are mounted onto the circuit board, at a stage prior to the engineering-trial manufacture of the component-mounted-circuit board,
where the first design evaluation is design evaluation for, with respect to the circuit design and electronic components selection, evaluating differences between an actually performed circuit design and a target circuit design, and between components selection and target components selection, the target circuit design and the target components selection being targeted for quality improvement in the assembly operation, in the assembly process, of mounting the electronic components onto the circuit board, and the second design evaluation is design evaluation for, with respect to design of the circuit board and pattern design of the circuit board, evaluating differences between an actually performed circuit board design and a target board design, and between a pattern design and a target pattern design.
As described in detail above, according to the design evaluating method for assisting circuit-board-assembly in the first aspect of the present invention, as well as to the design evaluating apparatus for assisting circuit-board-assembly in the fourth aspect of the present invention, the evaluation executing unit is provided and, prior to the engineering-trial manufacture of the component-mounted-circuit board, the first design evaluation or the second design evaluation is executed with considerations given to both sides of design and assembly, the design side where the circuit design and the pattern design are involved and the assembly process side where electronic components are mounted onto the circuit board. Therefore, prior to the engineering-trial manufacture of the component-mounted-circuit board, the evaluation of circuit design and components selection, or the evaluation of the board design and pattern design can be executed, thus enabling the evaluator, for example, the circuit designer to evaluate his or her own design by himself or herself, to grasp problematic points in assembly cost and assembly process, and to discuss the issues of assemblability on a scale common to the three divisions of the circuit design, the production technology and the assembly. More specifically, since failures that would occur during the production of circuits can be grasped in advance, solutions to the failures can be taken in advance, so that the development lead time can be reduced and that the number of times of engineering-trial manufacture can be reduced. Also, the product quality of circuits can be improved, and the cost reduction and the optimization of production efficiency can be achieved.
Further, according to the design evaluating method for assisting circuit-board-assembly in the second aspect of the present invention, as well as to the design evaluating apparatus for assisting circuit-board-assembly in the fifth aspect of the present invention, the evaluation executing unit is provided and, prior to the engineering-trial manufacture of the component-mounted-circuit board, the first design evaluation and the second design evaluation are executed with considerations given to both sides of design and assembly, the design side where the circuit design and the pattern design are involved and the assembly process side where electronic components are mounted onto the circuit board. Therefore, the evaluator, for example, the circuit designer is enabled to evaluate his or her own design by himself or herself. Also, since the evaluation of the present circuit design is enabled at the time when the circuit design and electronic-components selection has been completed, problematic points in assembly cost and assembly process can be grasped prior. to the engineering-trial manufacture. Further, it becomes also possible to perform a relative comparison between the circuit of the present design and a circuit of conventional design, and to discuss issues of assemblability on a scale common to the three divisions of the circuit design, the production technology and the assembly. More specifically, since failures that would occur during the production of the circuit can be grasped in advance, solutions to the failures can be taken in advance, so that the development lead time can be reduced and that the number of times of engineering-trial manufacture can be reduced. Also, product quality of the circuit can be improved, and a cost reduction as well as an optimization of production efficiency can be achieved.
Furthermore, according to the recording medium in the third aspect of the present invention, as well as to the design evaluating apparatus for assisting circuit-board-assembly in the fourth aspect of the present invention, information contained in the recording medium is read by the design evaluating apparatus for assisting circuit-board-assembly, making it possible to execute either the first design evaluation or the second design evaluation or both the first design evaluation and the second design evaluation prior to the engineering-trial manufacture of the component-mounted-circuit board. Therefore, the circuit designer is enabled to evaluate his or her own design by himself or herself with, for example, a personal computer. Also, since the evaluation of the circuit design is enabled at the time point, for example, when the circuit design and electronic-components selection has been completed, problematic points in assembly cost and assembly process can be grasped prior to the engineering-trial manufacture of a circuit board. Further, it becomes possible to perform a relative comparison between the circuit of the present design and a circuit of conventional design, and further to discuss issues of assemblability on a scale common to the three divisions of the circuit design, the production technology and the assembly. More specifically, since failures that would occur during the production of the circuit can be grasped in advance, solutions to the failures can be taken in advance, so that the development lead time can be reduced and that the number of times of engineering-trial manufacture can be reduced. Also, product quality of the circuit can be improved, and a cost reduction as well as an optimization of production efficiency can be achieved.